1. Field of Invention
The present invention relates to a data processing method performed with a color management module, suitable for image processing.
2. Related Art
Each computer peripheral appliance such as a scanner, a monitor, and a printer has its own color range. Usually, a picture that is laid out may have significant color differences through different peripherals. For example, the color of an image layout by printer may be slightly different from that is displayed on the monitor.
In order to solve the problem of output color difference of an image between different peripheral appliances, a color management module (CMM) is provided to equalize the color of the image layout provided by every peripheral.
In the CMM, a color management organization is installed in an operation system that includes a system configuration file defining the image capture and the color layout. The operation system usually has at least two configuration files. The CMM used for one peripheral may be different from the CMM used for other peripherals. Therefore, each peripheral requires its corresponding CMM independently.
Generally, objects to be processed in the computer are divided into three categories: text objects, graphic objects and image objects.
When the image objects are processed by the CMM, each pixel should be related to its corresponding color gamut, which causes a slow processing speed. For the text objects and the graphic objects, the colors of the text and graphic objects directly correspond to their corresponding color gamut's, and adjust the conversion of the whole memory block, thereby increasing the processing speed.
Although accessing-time of the memory for processing the text objects and the graphic objects is greatly reduced, this is not significant with respect to the total processing time, including the processing of the image objects. Especially when the whole page consists of image objects or when every object needs to undergo a raster operation.
An image display on a computer display device is achieved through RGB (red, blue and green) which are the main colors of a display color mode, while an image layout by printer or other peripherals is achieved through CMYK (cyan, magenta, yellow and black), which are the mains colors of the layout color mode.
Referring to FIG. 1, when the data or image shown on the computer display are to be laid out or printed, they are transmitted to an image-processing module 10 and are processed through a color management module 11, a half-toning/screening 12 and a compression 13. The data are transformed into the CMYK color mode and compressed for printing or scanning.
Half-toning processing is a process of conveying an image with a plurality of color-sublevels. In this process, the image is divided into a plurality of color spots, and indicated with a different density of color spots. For example, the light portion of color is displayed with a low density of color spots, while the more intense color portion is conveyed with a high density of color spots. Through a difference diffusion and screening, an image is generated with a half tone. The screening enables representing a color or gray graphic through re-organization of the spots.
However, when the printer processes the printing data, regardless of the computer site or the printer site, the image processing is proceeded at a limited speed because the CMM, the half-toning, the screening, and the compression are all performed at a specific site, for example, at the computer site or the printer site.
Furthermore, the data processing requires a lot of memory and processing capacity, which easily slows down the printing speed.